Method and apparatus for assembling parts

ABSTRACT

A method and an apparatus for adhering a part and a part support with the intermediary of intermediate members are disclosed. The method and apparatus are capable of assembling the part and part support while easily and accurately maintaining the intermediate members in a positional relation for adhesion relative to the part and part support.

BACKGROUND OF THE INVENTION

[0001] The present invention relates to a method and an apparatus forassembling parts and more particularly to a method and an apparatus forfixing with adhesive a part and a part support for mounting the part viaan intermediate member or members provided between the part and the partsupport.

[0002] Generally, to fix a part and a part support via a bracket-likeintermediate member positioned between the part and the part support, ithas been customary to fasten the part and part support and theintermediate member by using screws. Screws, however, are apt todisplace the part relative to the part support due to a torque when theyare driven, and thereby make it difficult to accurately position thepart.

[0003] In light of the above, the part and part support and theintermediate member may be so configured as to mate with each other in apreselected positional relation. Although this approach enhances thepositional accuracy of the individual structural element, it causes thepositional accuracy of the resulting assembly to be unconditionallydetermined by the finishing accuracy of the individual element. It istherefore necessary to machine the individual structural element withhigh accuracy. While this kind of approach reduces the assembling cost,it increases the material and machining costs of the individualstructural element. This is particularly true when the parts are plasticmoldings apt to scatter in accuracy due to sinking and other causes.

[0004] To assemble the part and part support via the intermediate memberwithout being effected by the finishing accuracy of the individualelement while maintaining them in an accurate positional accuracy, it isdesirable to connect the part, part support and intermediate member byusing adhesive. This, however, brings about a problem that whether ornot the part and part support are dislocated at the time of adhesiondetermines the positioning accuracy of the part relative to the partsupport after adhesion. It follows that the positional relation betweenthe part and the part support at the time of adhesion has criticalinfluence on the quality of the resulting product.

[0005] For example, assume that the above part is a print head includedin a printer, a line sensor included in a scanner, or a solid imagingdevice included in a CCD (Charge Coupled Device) camera. Then, when anypositional error occurs between the part and the part support, itdisplaces an image printed or read by the part and thereby deterioratesimage quality.

[0006] Particularly, when the part is an ink jet head included in an inkjet printer, it occurs that the distance between the head surface of thehead formed with nozzle holes and a recording medium is scattered orthat the nozzle holes fail to accurately face a position where an imageshould be printed on the recording medium. As a result, ink dropsejected from the nozzle holes reach the recording medium outside of apreselected printing position, noticeably lowering the image quality. Inthe case of a color printer including heads respectively loaded with inkof different colors (usually yellow ink, magenta ink, cyan ink and blackink), any positional error between the heads makes the print positionsof ink drops of different colors irregular. This brings the differentcolors forming a color image out of register or causes the color imageto distort.

[0007] The prerequisite with the adhesive scheme is therefore that thepart and the part support be accurately held, beforehand, in apreselected positional which will allow the part and part support toaccurately face an assembly position at the time of adhesion. In thisconnection, in the case of the head of a color printer, the allowableerror of the head adhered to the part support should be confined in therange of the order of microns.

[0008] As for the adhesive scheme, the positional relation between thepart and the part support at the time of adhesion is a critical factorthat determines the accuracy of mounting of the part to the partsupport, as stated earlier.

[0009] It has been customary with a method and an apparatus forassembling, e.g., the head of an ink jet printer to use a CCD cameraincluding a solid imaging device. The CCD camera picks up the nozzlehole formed in the head surface in the direction perpendicular to thehead surface. A computing section computes the position of the center ofgravity of the resulting image and thereby measures the positions of thehead in the directions of X and Y axes. At the same time, a control andoperation unit calculates the position of the head in the direction ofthe Z axis on the basis of data output from an autofocus device includedin the camera and relating to the amount of defocus in the Z axisdirection. The head surface and nozzle hole are adjusted in positionrelative to the part support on the basis of the result of measurement.

[0010] The above conventional CCD camera scheme has the followingproblem left unsolved. Assume that the camera is focused on a singlenozzle hole formed in the head surface for measurement. Then, thepositions of the nozzle hole in the X, Y and Z axis directions can beaccurately determined. However, it is impossible to accurately measure,based on the positions of the single nozzle, the deviation of the othernozzles holes ascribable to the irregularity or the rotation of the headsurface. It is therefore extremely difficult to correct such deviationof the other nozzles on the basis of the positions of the single nozzlehole. Consequently, a long period of time and sophisticated calculationsare necessary for the head to be positioned, obstructing rapid headassembly and simple measurement.

[0011] Another conventional method and apparatus for connecting thepart, part support and intermediate member uses three different chucks.A first chuck holds the part support and locates it at a preselectedassembly position. A second chuck holds the part in a positionadjustable relative to the part support. The position of the part isvaried while being monitored via a CCD camera in order to adjust itrelative to the part support at the assembly position. As a result, thepart and part support are accurately positioned relative to each other.After a third chuck has located the intermediate member between the partand the part support, the intermediate member and the part and partsupport are adhered together.

[0012] However, the prerequisite with the above chuck scheme is that thechucks, a measuring unit included in the CCD camera and an adhesiveapplying unit be prevented from interfering with each other. To meetthis requirement, each of the chucks and various units needs acomplicated structure and must be controlled in an extremelysophisticated way. Moreover, the layout of the chucks and units areseverely limited.

[0013] Further, to reduce the overall size of the unit made up of theintermediate member, part and part support, the intermediate membershould preferably be reduced in size as far as possible. Assume that thethird chuck is so configured as to hold such a small intermediate memberwith mechanical holding means. Then, it is necessary to adjust the forceof the holding means and to control a holding portion included in theholding means with utmost accuracy, so that the intermediate member willnot be damaged or will not slip out of the chuck.

[0014] Particularly, assume that the unit includes a plurality ofintermediate members supporting a single part. Then, to hold theintermediate members by using the above mechanical holding means andmove them to a preselected mounting position at the same time, the chuckmust have its construction complicated to a noticeable degree. Further,assume that adhesive applying means applies adhesive to the expectedsurfaces of the intermediate members being held by the holding means.Then, it is likely that the adhesive feed portion of the adhesiveapplying means contacts the surfaces of the intermediate members held bythe holding means and dislocates them.

[0015] As stated above, the apparatus of the type holding theintermediate member or members with mechanical holding means needs morecomplicated adjustment, control and construction and results in agreater size as the size of the individual intermediate member decreasesor as the number of the intermediate members increase.

SUMMARY OF THE INVENTION

[0016] It is therefore an object of the present invention to provide amethod and an apparatus capable of assembling parts while easily andaccurately maintaining intermediate members in a positional relation foradhesion relative to a part and a part support.

[0017] It is another object of the present invention to provide a methodand an apparatus capable of assembling a part, a part support andintermediate members with a simple construction.

[0018] It is a further object of the present invention to provide amethod and an apparatus capable of assembling parts while conveyingintermediate members relative to a part and a part substrate with simpleand easy holding and conveying means.

[0019] In accordance with the present invention, a method of assemblinga part and a part support by use of adhesive via an intermediate memberprovided between the part and the part support includes the steps ofpositioning and holding the part support at a preselected assemblingposition, and varying, while holding the part in a position adjustablerelative to the part support, the position of the part and detectingthree preselected points of the part to thereby adjust the position inwhich the part is to be mounted to the part support.

[0020] Also, in accordance with the present invention, an apparatus forassembling a part and a part support by use of adhesive via anintermediate member provided between the part and the part supportincludes a part support holding portion for positioning and holding thepart support at a preselected assembling position. A part supportingportion supports the part in a position variable relative to the partsupport held by the part support holding portion. A part positiondetecting section detects preselected three points of the part supportedby the part supporting portion. A part position adjusting sectionadjusts, based on the positions of the three detected points, theposition of the part relative to the part support.

[0021] Further, in accordance with the present invention, a method ofassembling a part and a part support by use of adhesive via anintermediate member provided between the part and the part supportbeging with the step of preparing a jig. The jig includes a part supportholding portion for positioning and holding the part support such thatthe part support remains in an assembly position and maintains portionsthereof for mounting the part and intermediate member open, a partsupporting portion for supporting the part in such a manner as to securea region for adjusting the position of the part relative to the partsupport positioned on the part support holding portion, and anintermediate member supporting portion for supporting the intermediatemember in a position ready to be mounted to the part support positionedon the part supporting holding portion. The part, part support memberand intermediate member are mounted to the jig. The position of the partis adjusted relative to the part support, and the intermediate member ismounted after the jig has been positioned at a preselected assemblingposition.

[0022] Furthermore, in accordance with the present invention, anapparatus for assembling a part and a part support by use of adhesivevia an intermediate member provided between the part and the partsupport includes a jig. The jig includes a part support holding portionfor positioning and holding the part support such that the part supportremains in an assembly position and maintains portions thereof formounting the part and intermediate member open, a part supportingportion for supporting the part ii such a manner as to secure a regionfor adjusting the position of the part relative to the part supportpositioned on the part support holding portion, and an intermediatemember supporting portion for supporting the intermediate member in aposition ready to be mounted to the part support positioned on the partsupporting holding portion. A jig positioning device positions at apreselected assembly position the jig loaded with the part, part supportmember and intermediate member in the part supporting portion, partsupport holding portion and intermediate member supporting portion,respectively.

[0023] Moreover, in accordance with the present invention, in a partassembling apparatus including a holding and conveying device forholding an intermediate member expected to fix a part and a part supportvia adhesive and conveying the intermediate member to a preselectedmounting position between the part and the part support, the holding andconveying device comprises an air chuck for retaining the intermediatemember thereon by vacuum.

BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The above and other objects, features and advantages of thepresent invention will become more apparent from the following detaileddescription taken with the accompanying drawings in which:

[0025]FIG. 1 is an external perspective view of a head unit assembled byan apparatus embodying the present invention;

[0026]FIG. 2 is a block diagram schematically showing the illustrativeembodiment;

[0027]FIG. 3 is a front view showing the general construction of theillustrative embodiment;

[0028]FIG. 4 is a perspective view showing the structural parts of thehead unit and a jig for conveying the parts to a preselected mountingposition;

[0029]FIGS. 5 and 6 are flowcharts demonstrating a specific operation ofthe illustrative embodiment;

[0030]FIG. 7 is a perspective view showing the jig positioned at asetting position defined on a set stage included in the illustrativeembodiment;

[0031]FIG. 8 is a perspective view showing a mechanism provided on anassembly stage included in the illustrative embodiment for positioningthe jig;

[0032]FIG. 9 is a perspective view showing a position adjusting unit foradjusting the position of the head surface of an ink jet head by holdingthe head;

[0033] FIGS. 10A-10C demonstrate a sequence of steps for causing headclamping means included in the position adjustment unit of FIG. 9 toclamp the ink jet head;

[0034]FIG. 11 is a perspective view of nozzle hole measuring meansincluded in the illustrative embodiment for detecting preselected threeof nozzle holes formed in the ink jet head;

[0035]FIG. 12 is a side elevation showing an intermediate membermounting unit for transferring intermediate members set on the jig to apreselected assembly position between a head support and the ink jethead, and adhesive applying means for applying UV (Ultra Violet) curableadhesive to the intermediate members;

[0036]FIGS. 13A and 13B are sections showing the behavior of theintermediate members transferred to the assembly position by theintermediate member mounting unit; and

[0037]FIG. 14 is a side elevation a head fixing unit for curing theadhesive applied to the intermediate members with UV rays.

DESCRIPTION OF THE PREFERRED EMBODIMENT

[0038] A preferred embodiment of the present invention will be describedhereinafter. The embodiment is implemented as a head unit assemblingapparatus for assembling an ink jet head unit (head unit hereinafter)included in a color ink jet printer by way of example.

[0039]FIG. 1 shows the general construction of the head unit to whichthe illustrative embodiment is applied. As shown, the head unit,generally 1, includes four heads or parts 2. A head support 3 supportsthe heads 2 and, in this sense, plays the role of a part support.Intermediate members 4 are arranged between the head support 3 and theheads 2 and adhered to connect them together. The heads 2 are thereforesupported by the head support 3 via the intermediate members 4.

[0040] As shown in FIGS. 3 and 4, each head 2 includes a nozzle-like inkfeed portion 2 a for feeding ink from an ink cartridge, not shown,mounted to the back of the head 2. The ink fed via the ink feed portion2 a is ejected from a number of nozzle holes 2 b in the form of finedrops toward a paper or similar recording medium. A control board, notshown, is mounted on the back of the head 2 for controlling the ejectiontiming of the ink drops via the nozzle holes 2 b. A control signal, aswell as other signals, is fed to the control board via a flexible flatcable 2 c. The nozzle holes 2 b of each head 2 are arranged in twoarrays in a head surface 2 d facing the paper, and each array extends inthe direction of paper transport (subscanning direction).

[0041] As shown in FIG. 1, the head support 3 includes substantiallyvertical head support walls 3 a supporting the heads 2 via theintermediate members 4 such that the head surfaces 2 d are exposed fromthe back toward the front. The head support 3 is mounted on a head unitsupport shaft, not shown, and movable back and forth in the direction(main scanning direction) perpendicular to the direction of papertransport. The head unit support shaft is mounted on the body of thecolor printer. Specifically, slide bearings 3 b are slidably mounted onthe above head unit support shaft. A bracket 3 c is positioned at therear of the head support 3 in order to hold ink cartridges respectivelymounted to the ink feed portions 2 a of the heads 2.

[0042] Each head 2 is adhered to the head support walls 3 a via fourintermediate members 4. As shown in FIG. 4, each intermediate member 4is implemented by a generally L-shaped piece having a substantiallyperpendicular first surface 4 a and a substantially horizontal secondsurface 4 b. The first surface 4 a is parallel to the head support wall3 a of the head support 3 while the second surface 4 b is parallel tothe upper surface of a base portion 2 e included in the head 2. Thecontrol board mentioned earlier is built in the base portion 2 e. Theintermediate members 4 are formed of transparent resin transparent forUV rays, so that UV curable adhesive applied to the surfaces 4 a and 4 bcan be cured via the members 4.

[0043]FIG. 2 is a block diagram schematically showing the apparatus forassembling the head unit 1. FIG. 3 shows a specific structure of theapparatus. As shown, the apparatus includes a jig 100, a jig conveyingunit or jig conveying means 200, a jig positioning unit 300, anintermediate member mounting unit 400, a head position adjusting unit500, a nozzle position measuring and head fixing unit 600, and a controland operation unit 700.

[0044] The jig 100 is loaded with the parts of the head unit 1, i.e.,the heads 2, head support 3, and intermediate members 4 to be assembled.

[0045] As shown in FIG. 3, the illustrative embodiment includes two jigs100 respectively located at setting positions A and B defined on a setstage 201. The jig conveying unit 200 includes a conveying mechanism202. The conveying mechanism 202 conveys the jig 100 back and forthbetween the setting position A or B and an elevating position C definedon the set stage 201 where the jig 100 is movable in the up-and-downdirection. An elevating mechanism 203 moves the jig 100 located at theelevating position C up and down between the set stage 201 and anassembly stage 301 positioned above the set stage 201.

[0046] The jig positioning unit 300 includes a clamping mechanism 302for clamping the jig 100 raised to the assembly stage 301. A positionadjusting mechanism 303 moves the clamping mechanism 302 clamping thejig 100 back and forth between an elevating position D and an assemblingposition E (see FIG. 8) defined on the assembly stage 301, therebyadjusting the stop position of the jig 100 on the stage 301. Measuringmeans 304 measures the position of the jig 100 moved by the positionadjusting mechanism 303.

[0047] The intermediate member mounting unit 400 includes a holdingmechanism 401 for holding the intermediate members 4 set on the jig 100that is located at to the assembling position E. The holding mechanism401 causes the intermediate members 4 to face a preselected adhesiveapplying position. A position adjusting mechanism 402 moves the holdingmechanism 401 holding the intermediate members 4 to a preselectedmounting position between each head 2 and the head support 3 set on thejig 100, thereby adjusting the mounting position of the members 4Adhesive applying means 403 applies UV curable adhesive to theintermediate members 4 held by the holding mechanism 401. Adhesiveadjusting means 404 adjust the amount of the adhesive to be applied tothe intermediate members 4 by the applying means 403.

[0048] The head position adjusting unit 500 includes head clamping means501 for clamping each head 2 set on the jig 100 having been brought tothe assembling position E. A position adjusting mechanism 502 moves thehead clamping means 501 in the directions parallel to the X axis whichis parallel to the direction of movement of the jig clamping mechanism302, directions parallel to the Y axis and the Z axis perpendicular tothe X axis, and directions of rotations α, β and γ having centers ofrotation respectively defined by the X, Y and Z axes, i.e., in sixdifferent directions in total. The position adjusting mechanism 502adjusts the position of the head 2 clamped by the clamping means 501.

[0049] The nozzle position measuring and head fixing unit 600 includes aCCD camera or part position detecting means 601 for detecting the nozzleholes 2 b of each head 2. Measuring means 602 measures the position ofpreselected ones of the nozzle holes 2 b on the basis of data outputfrom the CCD camera 601. A light source 604 illuminates the nozzle holes2 b to be detected by the camera 601 via a halogen light guide 603. A UVlight source 606 illuminates, via UV light guides 605, the intermediatemembers 4 brought to the preselected mounting position with UV rays.

[0050] The control and operation unit 700 includes a host controller orsequencer and a subcontroller or personal computer. The host controllermainly controls the operation of units driven by air cylinders. Thesubcontroller controls the operation of units driven by motors andperforms logical and arithmetic operations with image data and measureddata output from the various measuring means.

[0051] Reference will be made to FIGS. 5 and 6 for describing a specificoperation of the illustrative embodiment. A program for executing theoperation to be described is stored in, e.g., a ROM (Read Only Memory)included in the control and operation unit 700 beforehand and startswhen a main switch, not shown, included in the apparatus is turned on.

[0052] First, the apparatus is initialized (step S1). By theinitialization, the various units of the apparatus each is returned tothe respective home position. For example, the jigs 100 are respectivelybrought to the setting positions A and B on the set stage 201. Theoperator sequentially sets the various parts of the head unit 1 on thejigs 10 located at the positions A and B (step S2).

[0053] Specifically, each jig 100 is made up of a head support holdingportion, a head supporting portion, and an intermediate membersupporting portion. The head support holding portion holds the headsupport 3 such that the support 3 remains in its orientation forassembly maintains its portions for receiving the heads 2 andintermediate members 4 open or freely accessible. The head supportingportion supports the heads 2 in such a manner as to guarantee a regionfor adjusting the positions of the heads 2 relative to the head support3 positioned on the head support holding portion. The intermediatemember supporting portion supports the intermediate members 4 in such aposition that the members 4 can be transferred to the head support 3positioned on the head support holding portion.

[0054] As shown in FIGS. 3, 4 and 7, the head support holding portionincludes a stationary stub 102 fixed to a rear side wall 101 included inthe jig 100. A movable stub 104 is mounted on a front side wall 103 alsoincluded in the jig 100 and faces the stationary stub 102. The movablestub 104 is movable toward and away from the stationary stub 102. Apush-down member 106 is mounted on a pair of brackets 105 respectivelyfixed to the upper right portions of the inner surfaces of the sidewalls 101 and 103. Three push-up members 107 are positioned on thebottom wail 113 of the jig 100 in order to push up the head support 3.The stubs 102 and 104 each has the same outside diameter as the headunit support shaft mentioned earlier. A lug 106 a protrudes fromsubstantially the center of the underside of the push-down member 106.The lug 106 a faces the bracket 3 c of the head support 3 remote fromthe slide bearings 3 b.

[0055] The movable stub 104 extends throughout the side wall 103 and isfixed to a bracket 108 positioned outside of the side wall 103. Anotherbracket 109 is mounted on the outer surface of the side wall 103. Thebracket 108 is mounted on a shaft 110 journalled to the bracket 109 andside wall 103 and is slidable in the direction parallel to the axis ofthe movable stub 104. A coil spring 111 is wound round the shaft 110 andconstantly biases the bracket 108 toward the side wall 103. A lever 112to be operated by hand is mounted on the bracket 108 and received in aguide slot 109 a formed in the bracket 109.

[0056] The head support 3 is set on the head support holding portion bythe following procedure. Before setting the head support 3, the operatorpulls the lever 112 toward the operator against the action of the coilspring 111 and locks it in a locking portion included in the guide slot109 a. As a result, the movable stub 104 moves toward the outside of theside wall 103, making the distance between the surfaces of the stubs 104and 102 facing each other greater than the maximum width between theslide bearings 3 b. In this condition, the operator coupled the rearslide bearing 3 b of the head support 3 to the stationary stub 102 andunlocks the lever 112. Consequently, the movable stub 104 mates with thefront slide bearing 3 b of the head support 3 due to the action of thecoil spring 111. Subsequently, the operator sets the three push-upmembers 107 to a preselected height and mounts the push-down member 106to the brackets 105. The lug 106 a of the push-down member 106 pushesthe bracket 3 c of the head support 3 downward.

[0057] By the above procedure, the head support 3 is set at apreselected position on the jig 100. In the head support holdingportion, the stationary stub 102 and movable stub 104 support the slidebearings 3 b of the head support 3 in the same manner as the head unitsupport shaft which allows the heads 2 to move in the main scanningdirection, as stated above. Therefore, by using the stubs 102 and 104 asa reference axis for mounting the heads 2 to the head support 3, it ispossible to extremely accurately position the heads 2 relative to thehead support 3. In addition, the three push-up members 107 positioned onthe bottom wall 113 of the jig 100 support the back of the head support3 and thereby insure the horizontal position of the head support 3.

[0058] The head supporting portion is implemented by a head supportmember 115 fixed to the side walls 101 and 103 at substantially theintermediate between the side walls 101 and 103. The head support member115 is located at a position allowing the heads 2 to be adjusted inposition relative to the head support 3 positioned on the head supportholding portion. As shown in FIGS. 3, 4 and 7, the head support member115 is formed with four surfaces 115 a for positioning the base portions2 e of the four heads 2. Holes 115 b are formed in the head supportmember 115 such that when the heads 2 are laid on the surfaces 115 a,the ink feed portions 2 a of the heads 2 are respectively received inthe holes 115 b. A cable pocket 115 c is also formed in the head supportmember 115 for accommodating the flexible flat cables 2 c of the heads2. The head support member 115 is configured such that when the heads 2are laid on the surfaces 115 a, the heads 2 each faces the lower portionof the respective head mounting portion between the head support walls 3a of the head support 3 (see FIG. 3).

[0059] The ink feed portion 2 a of each head 2 is received in therespective hole 115 b of the head support member 115, therebypositioning the head 2 on the respective surface 115 a. This eliminatesthe need for special positioning means. When the heads 2 are positionedon the head support member 115, the cables 2 c of the heads 2 areaccommodated in the cable pocket 115 a. Therefore, the clamping means501 which will be described later can clamp the heads 2 without beingobstructed by the cables 2 c.

[0060] The intermediate member supporting portion is implemented by aflat intermediate member support member 116 similar to the head supportmember 115. The intermediate member support member 116 is fixed to theupper left portions of the inner surfaces of the side walls 101 and 103and substantially parallel to the bottom wall 113. As shown in FIGS. 3,4 and 7, two parallel grooves 116 a are formed in the support member 116perpendicularly to the side walls 101 and 103. Positioning pins 116 bare studded on the bottom of each groove 116 a at equally spacedlocations. Each intermediate member 4 is positioned on the supportmember 116 with its first surface 4 a and second surface 4 brespectively contacting any one of the pins 116 b and the bottom ofeither one of the grooves 116 a.

[0061] The distance between the grooves 116 a, the width of each grooveand the distance between the positioning pins 116 b are selected suchthat when the intermediate members 4 are set on the intermediate membersupport member 116, the members 4 have substantially the samearrangement as when they are mounted to the head support 3 and heads 2.This successfully simplifies the adjustment of the positions of theintermediate members 4 to be effected by the holding mechanism 401 andposition adjusting mechanism 402 which will be described later, andtherefore the configurations and control of the mechanisms 401 and 402.

[0062] As shown in FIGS. 4 and 7, the jig 100 includes two stays 114 inaddition to the bottom wall 113 and has an open top. Therefore, theparts of the head unit 1 can be set on the jig 100 from above the jig100. This promotes rapid setting of the parts and rapid removal of thehead unit 1 and enhances the free layout of the nozzle positionmeasuring and fixing unit 600. Further, an opening 113 a is formed inthe bottom wall 110 below the head support member 115, so that theclamping means 501 which will be described can reach the inside of thehead support 3 from the back side.

[0063] The clamping means 501 is allowed to clamp each head 2 from theback side of the head support 3, as stated above. It follows that thenozzle position measuring and fixing unit 600 can be laid out withgreater freedom above the head support 3, and the head unit 1 can bereduced in size and increased in strength. By contrast, if the head 2 ismounted to the head support 3 from above the head support 3, then eachopening 3 d (see FIG. 4) formed in the head support 3 for receiving thehead 2 must be greater in size than the base portion 2 e of the head 2.This increases the distance between the nearby walls 3 a of the headsupport 3 and therefore the size of the head support 3 while reducingthe strength of the walls 3 a holding the heads 2.

[0064] After the parts of the head unit 1 have been set on the jig 100by the above procedure, a step S3 shown in FIG. 5 is executed. In thestep S3, whether or not the operator has turned on start switches SW1and SW2 substantially at the same time for causing the conveyance of thejig 100 to start. As shown in FIG. 3, the start switches SW1 and SW2 arepositioned on the set stage 201 in the vicinity of the opposite settingpositions A and B at a suitable distance, so that they will not turn onunless the operator touches them with both hands. This prevents theoperator's hands from being hurt when the jig 100 starts moving.

[0065] The jig conveying mechanism 202 for conveying the jig 100includes two cylinders 204 a and 204 b. When the two start switches SW1and SW2 are turned on substantially at the same time, the cylinder 204a, for example, assigned to the setting position A is turned on (stepS4).

[0066] The cylinders 204 a and 204 b each is implemented by an aircylinder and mounted on a cylinder guide shaft 205 (see FIGS. 3 and 7)in such a manner as to be movable back and forth. The cylinder guideshaft 205 is supported by a pair of brackets 206 mounted on oppositesides of the set stage 201 and extends in parallel to the set stage 201.Bases 207 a and 207 b are respectively loaded with the jigs 100 andposition them at the setting positions A and B. The cylinders 204 a and204 b are respectively fixed to the lower portions of the bases 207 aand 207 b via cylinder brackets 208.

[0067] The bases 207 a and 207 b carry the jigs 100 identical inconfiguration with each other. The following description willconcentrate on the base 207 a located at the setting position A, i.e.,the left position in FIG. 3 by way of example.

[0068] As shown in FIGS. 3 and 7, the jig elevating mechanism 203 whichwill be described includes a table 209 for elevating the jig 100. Thefour sides of the bottom wall 113 of the jig 100 can be positioned atsubstantially the center of the upper surface of the base 207 a. Anopening 207 c great enough to receive the table 209 is formed insubstantially the center of the base 207 a. A plate 210 formed ofacrylic resin is fitted on the base 207 a around the opening 207 a, sothat the jig 100 will be positioned slightly above the upper surface ofthe base 207 a.

[0069] Five crank-like jig positioning members 211 are fixed to theupper surface of the base 207 a at the front, rear and left of the plate210, as viewed in FIG. 7, such that the members 211 respectively contactthree sides of the bottom plate 113. A pair of guide rails 212 areprovided on the set stage 201. Rail guides 213 are provided at fourcorners of the underside of the table 207 a and respectively slidablyengaged with the guide rails 212. The guide rails 212 are parallel tothe cylinder guide shaft 205. A presser 214 is positioned at theright-hand side of the base 207 a in order to stop the jig 100 againstinertia when the base 207 a is brought to a stop.

[0070] When the cylinder 204 a is turned on (step S4), the jig conveyingmechanism 202 moves the base 207 a from the setting position A, FIG. 3,to the elevating position C. When the bracket 208 of the cylinder 204 aabuts against a stop 215 located at substantially the center of the setstage 201, the cylinder 204 a stops moving. The position where thecylinder 204 a stops moving is selected such that when the cylinder 204a stops, the table 209 of the jig elevating mechanism 203 facessubstantially the center of the opening 207 c of the base 207 a.

[0071] When the jig 100 is brought to a stop at the elevating positionC, i.e., at substantially the center of the set stage 201, the presser214 driven by an air cylinder, not shown, stops pressing the jig 100.Then, a cylinder 216 for moving the table 209 up and down is turned on(step S5) in order to elevate the table 209. The cylinder 216 alsoimplemented by an air cylinder is constructed to raise or lower a tablesupport 209 supporting the table 209 when turned on or turned off. Asshown in FIGS. 3 and 7, the cylinder 216 is mounted on a support plate218 which is mounted on the underside of the set stage 201 via acylinder stay 218.

[0072] A positioning pin 220 is studded on the upper surface of thetable 209 while a hole 221 for receiving the pin 220 is formed in thebottom wall 113 of the jig 100. When the cylinder 216 is turned on toraise the table 209, the positioning pin 220 enters the hole 221 withthe result that the jig 100 is positioned on the table 209. As the table209 is further raised, the jig 100 set on the base 207 a and brought tothe elevating position C is transferred to the table 209. As a result,as shown in FIG. 3, the jig 100 is raised by the table 209 to theelevating position C of the assembly stage 301 positioned above the setstage 201.

[0073] As shown in FIGS. 3 and 8, a relatively large elongate opening301 a is formed in substantially the center of the assembly stage 301.The opening 301 a has a width allowing the jig 100 to pass therethroughand a length spanning the distance between the elevating position D andthe assembling position E. A pair of guide rail s 305 extend on theupper surface of the assembly stage 301 at both sides of and in thelengthwise direction of the opening 301 a. The guide rails 305 extendperpendicularly to the direction in which the jig 100 is moved on theset stage 201, thereby guiding the jig positioning unit 300.

[0074] Rail guides 307 are mounted on four corners of the underside of abase 306 on which the clamping mechanism 302 is mounted. The rail guides307 are engaged with the guide rails 305, so that the base 306 ismovable back and forth along the guide rails 305. The base 306 has achannel-like configuration surrounding the path along which the jig 100is elevatable. The clamping mechanism 302 includes a stationary clampmember 308 and a movable clamp member 308 respectively positioned at therear and the front of the base 306.

[0075] Two clamp pins 310 are studded on the stationary clamp member 308and respectively mate with holes 118 a (see FIG. 7) formed in a member118 to be clamped and mounted on the rear side wall 101 of the jig 100.A single clamp pin 311 is studded on the movable clamp member 309 andmates with a single hole 119 a formed in a member 119 to be clamped andmounted on the front side wall 103. A cylinder 312 implemented by an aircylinder drives the movable clamp member 309 toward and away from thestationary clamp member 308. The movable clamp member 309 is usuallyretracted to the front side of the base 306 such that the clamp pin 311does not protrude into the elevation path of the jig 100. An opening 306a is formed in the base 306 in such a position that when the movableclamp member 309 is retracted, the clamp pins 310 of the stationaryclamp member 308 and the clamp pin 311 of the movable clamp member 309each is positioned outside of the elevation path of the jig 100.

[0076] When the cylinder 216 is turned on (step S5, FIG. 5), the table209 raises the jig 100 to the elevating position D on the assembly stage301, i.e., the position where the clamp pins 310 and 311 respectivelyface the members 118 and 119 a. When the jig 100 is brought to a stop atthe position D, the cylinder 312 is turned on (step S6).

[0077] When the cylinder 312 is turned on, it moves the movable clampmember 309 toward the stationary clamp member 308. As a result, theclamp pins 310 and 311 of the clamp members 309 and 308 respectivelymate with the holes 118 a and 119 a of the jig 100, so that the jig 100is clamped by the base 306. Subsequently, a motor 313 included in theposition adjusting mechanism 303 is turned on for moving the base 306back and forth along the guide rails 305 (step S7).

[0078] As shown in FIG. 8, the motor 313 is a reversible motor fordriving a ball screw 314 via a speed reduction gear not shown. A ballnut 315 including a steel ball is held in threaded engagement with theball screw 314. The ball nut 315 is fixed to the base 306 via achannel-shaped bracket 316. As shown in FIGS. 3 and 8, the motor 313 ismounted on screen-like support members 317 mounted on the right portionof the assembly stage 301 at the front side and rear side, respectively(only the rear support member is shown). A support plate 318 is fixedbetween the upper surfaces of the support members 317. The ball screw314 is journalled to bearings 31 respectively fixed to the front end andrear end of the support plate 318.

[0079] When the motor 313 causes the ball screw 314 to rotate in theforward direction (step S7), the base 306 moves along the guide rails305 to the rear of the assembly stage 301. As a result, the jig 100clamped by the base 306 is moved from the position D to the position Eon the assembly stage 301. A linear scale 320 is fixed to the base 306while a scale measuring portion 321 is fixed to the assembly stage 301.The scale measuring portion 321 measures the displacement of the linearscale 320 while sending the result of measurement to the control andoperation unit 700. In response, the control and operation unit 700selectively turns on or turns off the motor 313 and thereby controls thedisplacement of the base 306 with utmost accurately.

[0080] Whether or not the base 306 has reached the assembling position Eis determined (step S8). If the answer of the step S8 is positive (Y),the motor 313 is turned off (step S9). As a result, the jig 100 carriedon the base 306 is accurately brought to a stop at the position E. Whenthe heads 2, head support 3 and intermediate members 4 set on the jig100 each faces a particular assembly start position, a motor ZM includedin the position adjusting mechanism 502 and assigned to the Z axis isturned on (step S10).

[0081] As shown in FIG. 9, the motor ZM causes a Z axis base 510 to moveup and down along the Z axis perpendicular to the base 306. The motor ZMis fixed to a Y axis table 511. A motor YM assigned to the Y axis causesthe Y axis table 511 to move in the X axis direction parallel to thedirection of movement of the base 306 and the Y axis directionperpendicular to the Z axis direction. The motor YM is fixed to an Xaxis base 512 driven by a motor XM in the X axis direction.

[0082] The motor XM is fixed to a Z axis rotation base 513. A motor ZRMcauses the table 513 to rotate in the γ direction about the Z axis. Amotor XRM is mounted on the Z axis base 510 for causing an X axisrotation base 514 to rotate in the α direction about the X axis.Further, a motor YRM is mounted on the X axis base 514 and causes a Yaxis rotation base 515 to rotate in the β direction about the Y axis.

[0083] An arm support 503 and two cylinders 504 and 505 playing the roleof the clamping means 501 are mounted on the Y ax is rotation table 514.The cylinders 504 and 505 are implemented by air cylinders. As shown inFIG. 9, arms 507 and 508 stand upright on the tops of the cylinders 504and 505, respectively. The air cylinders 504 and 505 respectively movethe arms 507 and 508 back and forth in the Y axis directionperpendicular to the direction of movement of the base 306. An arm 506extends upward from the arm support 503 and faces the arms 507 and 508.

[0084] When the motor ZM assigned to the Z axis is turned on (step S10),it raises the Z axis base 510. Whether or not the arms 506, 607 and 508of the clamping mans 501 have risen to a preselected clamping positionis determined (step S11). If the answer of the step S11 is Y, the motorZM is turned off in order to stop the elevation of the table 510 (stepS12). As shown in FIGS. 9 and 10A, at the above clamping position, clamppins 506 a, 507 a and 508 a studded on the arms 506, 507 and 508 face toface, respectively, face holes 2 f formed in opposite ends of the base 2e of the head 2 supported by the head support member 115.

[0085] After the Z motor ZM has been turned off, the motor YM assignedto the Y axis is turned on (step S13). As shown in FIG. 10A, the motorYM moves the arm 506 toward the base portion 2 e of the head 2. As shownin FIG. 10B, clamp pin 506 a of the arm 506 mates with the hole 2 f ofthe base portion 2 e (step S14). Then, the motor YM is turned off (stepS15). Subsequently, the cylinders 504 and 505 are turned on (step S16).As shown in FIG. 10B, the cylinders 504 and 505 respectively move thearms 507 and 508 toward the base portion 2 e. Consequently, as shown inFIG. 10C, the clamp pins 507 a and 508 a of the arms 507 and 508 matewith the other holes 2 f of the head base 2 e.

[0086] After the clamp pins 507 a and 508 b have clamped the baseportion 2 e of the head 2 in cooperation with the clamp pin 506 a, themotor ZM assigned to the axis Z is again turned on (step S17). At thistime, the motor ZM raises the Z axis base 510 and therefore the arms506-508 to a preselected head mounting position (see FIG. 3). When thearms 506-508 reach the head mounting position, as determined in a stepS18, the motor ZM is turned off in order to stop the elevation of the Zaxis base 510 (step S19).

[0087] Thereafter, the nozzle position measuring means 602 is turned on(step S20, FIG. 6). The measuring means 602 measures the positions ofpreselected ones of the nozzle holes 2 b of the head 2 in the X, Y and Zaxe directions. This is successful to determine whether or not the headsurface 2 d raised by the clamping means 501 is accurately located atthe assembly position relative to the head support 3 positioned on thejig 100.

[0088] Conventional nozzle position measuring means picks up a singlenozzle hole 2 b formed in the surface 2 d with a CCD camera including asolid imaging device. An operating section calculates the position ofthe center of gravity of the resulting image and thereby determines thepositions of the head 2 in the X and Y axis directions. Further, theposition of the head 2 in the Z axis direction is determined on thebasis of defocus data output from an autofocus device built in thecamera.

[0089] The above conventional scheme is disadvantageous for thefollowing reasons. When the camera is focused on a single nozzle hole 2b in order to position the head 2, the positions of the single nozzlehole 2 b in the X, Y and X axis directions can be accurately positioned.However, it is impracticable to accurately measure, based on thepositions of the above nozzle hole 2 b, the positional deviation of theother nozzle holes 2 b ascribable to the irregularity and rotation ofthe surface 2 d.

[0090] With the conventional scheme therefore, it is extremely difficultto correct the positional deviation of the other nozzle holes 2 bascribable to the above causes. That is, a long period of time andcomplicated calculations are necessary for the head 2 to be positioned.

[0091] In the illustrative embodiment, the head 2 is held by theclamping means 501 and position adjusting mechanism 502 in such a manneras to be adjustable in position relative to the head support 3. In thiscondition, the position of the head 2 is varied in order to detect threepreselected points of the head 2 by using CCD cameras, so that the head2 can be adjusted relative to the head support 3. In the illustrativeembodiment, at least three CCD cameras assigned to the above threepoints have their optical axes inclined relative to the surface of thehead 2 to be detected, i.e., the head surface 2 d.

[0092] Specifically, as shown in FIGS. 3 and 11, the measuring means 602of the illustrative embodiment includes CCD cameras 601 a-601 e. Thecamera 601 a detects the position of, e.g., the leftmost nozzle hole 2b-1 of the front array, as viewed in FIG. 11, in the inclined direction.The camera 601 b detects the position of the nozzle hole 2 b-1 in thevertical direction. A halogen light guide 603 a guides halogen lightoutput from the light source 504 to the nozzle hole 2 b-1. The camera601 c detects the position of the rightmost nozzle hole 2 b-2 of thefront array, as viewed in FIG. 11, in the inclined direction. The camera601 d detects the position of the nozzle hole 2 b-2 in the verticaldirection. A halogen light guide 603 b guides the halogen light to thenozzle hole 2 b-2. The camera 601 e detects the position of the centernozzle hole 2 b-3 of the rear array, as viewed in FIG. 11, in theinclined direction. A halogen light guide 603 b guides the halogen lightto the nozzle hole 2 b-3 via a mirror 606 c.

[0093] As shown in FIG. 3, a top plate 331 is connected to the assemblystage 301 by a plurality of posts 330. A support plate 610 is mounted onthe top plate 331 and extends downward through an opening 331 a formedin substantially the center of the top plate 331. The measuring means602 is mounted on the support plate 610.

[0094] With the three CCD cameras 601-a through 601 c, it is possible todetect the nozzles 2 b-1 through 2 b-3 or three preselected points ofthe head surface 2 d and determine their positions on the X, Y and Zcoordinates. It is therefore not necessary to use the autofocus devicecustomarily assigned to the Z axis direction.

[0095] In the illustrative embodiment, the measuring means 602 detectsthe nozzle holes 2 b formed in the surface 2 d of the head. As for thesurface of a part lacking such portions to be detected, e.g., a solidimaging device, marks to be detected may be provided on the surfacebeforehand.

[0096] Assume that at least three CCD cameras have their optical axespositioned vertically to the head surface 2 d for detecting the abovethree points. Then, because the optical axes of the camera are parallelto each other, the distance between the optical axes is unconditionallydetermined by the outside diameter of the cameras. Therefore, when thehead 2 is relatively small and has the maximum distance between itsthree points smaller than the minimum distance between the optical axesof the cameras, the optical axes are positioned outside of the threepoints of the head 2. In this condition, the cameras cannot detect thethree points of the head 2.

[0097] By contrast, in the illustrative embodiment, the optical axes ofat least three CCD cameras 601 a through 601 c are inclined relative tothe surface 2 of the head 2 and can therefore be oriented in desireddirections. This successfully prevents the minimum distance betweenthree points that can be detected from being unconditionally determinedby the outside diameter of the cameras. That is, it is possible todetect desired three points of the head 2 and accurately position thehead 2 without regard to the size of the head 2.

[0098] Image data representative of the nozzle holes 2 b- through 2 b-3and output from the cameras 601 a through 601 e are monitored on the CRT(Cathode Ray Tube) of the subcontroller or personal computer via thecontrol and operation unit 700. Assume that the positions and shapes ofthe images being monitored are different from positions and shapes setbeforehand. Then, it is determined that the head surface 2 d does notaccurately face the head mounting position (step S21, FIG. 6). As aresult, the position adjusting mechanism 502, FIG. 9, is turned on (stepS22). Specifically, the motors of the mechanism 502 are driven to shiftthe head 2 in the six directions X, Y, Z, α, β and γ. When the surface 2d accurately faces the head mounting position (Y, step S21) themeasuring means 602 and adjusting mechanism 502 are turned off (stepS23).

[0099] The head 2 is positioned at the head mounting position relativeto the head support 3 by the above procedure. Subsequently, the positionadjusting mechanism 402 included in the intermediate member mountingunit 400 is turned on (step S24) in order to drive the holding mechanism401. As shown in FIGS. 3 and 12, the holding mechanism 401 includes twoair chucks 405 and 406 capable of simultaneously chucking fourintermediate members 4 necessary for adhering a single head 2 to thehead support 3.

[0100] As shown in FIG. 3, the air chucks 405 and 406 are fixed to theend portion of a chuck arm 407. When the air chucks 405 and 406 are heldin a home position, they are positioned right above the two grooves 116a, FIG. 4, of the intermediate member support member 116 set on the jig100. As shown in FIG. 12, the air chucks 405 and 406 each has arectangular lower end or chucking portion. With this configuration, eachof the air chucks 405 and 406 can hold two intermediate members 4located between two positioning pins 116 b studded in the associatedgroove 116 a, while maintaining the members 4 substantially in their setpositions. Passageways 405 a and 406 a are respectively formed in theair chucks 405 and 406 in order to selectively suck or blow air via thebottoms and opposite sides of their chucking portions.

[0101] A shaft 407 a is fixed to the base end of the chuck arm 407 andextends along the Y axis. The shaft 407 a is supported by a chuckbracket 408 in such a manner as to be rotatable by substantially 180degrees. A cylinder 409 implemented as an air cylinder supports thecheck bracket 408 such that the bracket 408 is movable up and down alongthe Z axis. As shown in FIG. 3, a robot 411 is mounted on a plate 410fixed to the rear side of the assembly stage 301. The robot 411 movesthe above cylinder 409 back and forth along the Y axis. A cylinder 412also implemented by an air cylinder is fixed to the chuck bracket 408and causes the shaft 407 a to rotate.

[0102] When the position adjusting mechanism 402 is turned on (stepS24), the cylinder 409 lowers the chuck bracket 408 along the Z axis. Asa result, the chucking portions of the air chucks 405 and 406 arelowered to a position where each of them can chuck two of theintermediate members 4 set on the support member 116, as indicated by anarrow a in FIG. 12. The lowered position of the air chucks 405 and 406is determined by a lower stop 409 a fixed to the lower portion of thecylinder 409; a positioning piece 408 a provided on the bracket 408abuts against the lower stop 409 a.

[0103] Subsequently, air is sucked via the passageways 405 a and 406 a,producing vacuum around the chucking portions of the air chucks 405 and405. As a result, the air chucks 405 and 406 retain two intermediatemembers 4 each.

[0104] After the air chucks 405 and 406 have chucked the intermediatemembers 4. the cylinder 409 operates in the reverse direction in orderto lift the chuck bracket 408 to a preselected level. Then, the cylinder412 causes the shaft 407 a to rotate by substantially 180 degrees, asindicated by an arrow b in FIG. 12. The cylinder 409 operating in thereverse direction lifts the chuck bracket 408 until the positioningpiece 408 a of the bracket 408 abuts against an upper stop 409 b fixedto the upper portion of the cylinder 409, as indicated by an arrow c inFIG. 12. Consequently, the intermediate members 4 retained by the airchucks 405 and 406 are turned upside down and cause their surfaces 4 aand 4 b to face the tops and both sides of the chucking portions of theair chucks 405 and 406.

[0105] The adhesive applying means 403 includes a pair of syringes 431positioned above the air chuck 405 and each having a pair of nozzles 430for applying the UV curable adhesive to the surfaces 4 a and 4 b of eachintermediate member 4. A heater 432 playing the role of the adhesiveadjusting means 404 surrounds the respective syringe 431. The heaters432 each maintains the UV adhesive at a preselected temperature (about30° C.) providing the adhesive with optimal viscosity.

[0106] As shown in FIG. 3, each syringe 431 is fixed to a bracket 436via a syringe holder 435. The bracket 436 is supported by a bracketholder 437 mounted on the underside of the top plate 331 and is slidablein the Y axis direction. The operator can therefore pull out thesyringes 431 to the left of the device body, FIG. 3, by holding a lover438 fixed to the bracket 406. This facilitates the replenishment of theUV curable adhesive to each syringe 431 and prevents the operator fromtouching the heater 432.

[0107] After the intermediate members 4 retained by the air chucks 405and 408 have been turned upside down, as stated above, the nozzles 430of the syringes 431 are caused to face the surfaces 4 a and 4 b of thetwo intermediate members 4 hold by the air chuck 405, as shown in FIG.12.

[0108] Subsequently, the adhesive applying means 403 is turned on (stepS25. Specifically, the UV curable adhesive is applied to the surfaces 4a and 4 b of the two intermediate members 4 held by the air chuck 405via the two nozzles 430 of the two syringes 431. After the applicationof the adhesive to the surfaces 4 a and 4 b of the above twointermediate members 4, the robot 411 shifts the other air chuck 406positioned at the left, as viewed in FIG. 3, rightward to the positionwhere the air chuck 405 has been positioned. As a result, the surfaces 4a and 4 b of the two intermediate members retained on the top and bothsides of the holding portion of the air chuck 406 by suction face thetwo nozzles 430 of the two syringes 431. Then, the adhesive applyingmeans 403 is again turned on in order to apply the adhesive to thesurfaces 4 a and 4 b via the nozzles 430 of the syringes 431.

[0109] After the application of the adhesive to the four intermediatemembers 4 held by the air chucks 405 and 406, the air chucks 405 and 406are returned to the previously mentioned home positions. At the sametime, the robot 411 moves the air chucks 405 and 406 to preselectedpositions above the assembling position between the head 2 held at themounting position and the head support 3. Subsequently, the cylinder 409is turned on to lower the air chucks 405 and 406. Consequently, as shownin FIG. 13A, the four intermediate members 4 held by the air chucks 405and 406 face the mounting position between the head 2 and the headsupport 3.

[0110] In the above condition, air is jetted via the passageways 405 aand 406 a of the air chucks 405 and 406. As a result, the surfaces 4 aand 4 b of the four intermediate members 4 are released from the airchucks 405 and 406 and brought into close contact with the expectedportions of the head 2 and head support 3. Thereafter, the air chucks405 and 406 are returned to their home positions, and then the positionadjusting mechanism 402 is turned off (step S26).

[0111] After the step S26, the head fixing unit 600 is turned on (stepS27). Specifically, as shown in FIG. 14, the two UV light guides 605retracted from the Y axis passage assigned to the air chucks 405 and 406are moved to a position above the head 2 by a cylinder or air cylinder620. In this condition, the UV light source 606 is turned on to issue UVrays toward the adhesive present on the surfaces 4 a and 4 b of theintermediate members 4 via the intermediate members 4. The adhesive iscured by the UV rays and fix the head 2 and head support 3 to each othervia the intermediate members 4.

[0112] An air tube 621 is positioned above each of the UV light guide605 and joined with the light guide 605 by a respective tie member 622.Air, preferably cool air, is blown out of such air tubes 621 toward theintermediate members 4 at the time of emission of the UV rays. This airprotects the intermediate members 4 from thermal deformation ascribableto the UV rays and obviates the displacement of the head 2 and headsupport 3 ascribable to thermal stress.

[0113] After the head 2 has been fixed to the head support 3 by theabove procedure, whether or not another head 2 should be fixed to thehead support 3 is determined (step S28). Assume that the apparatus is soprogrammed as to sequentially fix the other heads 2 to the head support3. Then, a head assembly routine for executing the above sequence ofassembling steps is repeatedly executed until all the predeterminednumber of heads 2 have been fixed to the head support 3 (step S29). Atthis time, the data derived from the position adjustment of thepreceding head 2 relative to the head support 3 are referenced asposition adjustment data when the following head 2 is fixed to the headsupport 3. When all the preselected number of heads 2 are fully fixed tothe head support 3 (N, step S28), the various units start returning totheir home positions (step S30).

[0114] At the beginning of the step S30, the measuring means 602 isagain turned on (step S31) to measure the positions of the threeparticular nozzle holes of each head 2. The result of this measurementshows whether or not the heads 2 are dislocated during assembly.Specifically, the control and operation unit 700 compares the dataoutput from the measuring means 602 before and after the assembly andsends the result of decision on the configuration of the heads 2 to theCRT (step S32). The program ends when the various units are returned totheir home positions (Y, step S33).

[0115] The illustrative embodiment has two setting positions A and B onthe set stage 201, as stated with reference to FIG. 3. The paths betweenthe setting positions A and B and the assembling position E along whichthe conveying unit 200 conveys the jigs 100 can be switched by thecontrol and computation unit 700. Therefore, it is possible to conveyone jig 100 conveyed from one setting position A to the assemblingposition E and completed assembly at the position E to the other settingposition B. It is also possible to feed one jig 100 from one settingposition A to the assembly position E and set, while the above jig 100has its parts assembled, the structural parts of another head unit onthe other jig 100 located at the other setting position B. Theillustrative embodiment therefore reduces the operator's waiting time atthe time of setting of the structural parts on the jig 100 and therebyenhances efficient assembly.

[0116] In summary, it will be seen that the present invention provides amethod and an apparatus for assembling parts having variousunprecedented advantages, as enumerated below.

[0117] (1) While a part support is positioned and held at a preselectedassembling position, a part retained is adjustable in position relativeto the part support. This, coupled with the fact that three preselectedpoints of the part are detected, allows the position of the part in thespace to be accurately detected and thereby promotes accurate positionadjustment of the part.

[0118] (2) Particularly, when a plurality of identical parts are to beaffixed to the part support in an identical condition, positionadjustment data derived from the preceding part are referenced a thetime of fixing the next part to the part support. This successfullyreduces a period of time necessary for the following part to be adjustedin position.

[0119] (3) At least three optical detecting means respectively assignedto the three points of the part have optical axes inclined relative tothe surface of the part to be detected. Therefore, the positions of thethree points on the X, Y and Z coordinates can be determined withoutresorting to, e.g., an autofocus device. Because the positions of suchoptical axes can be freely set, the minimum distance between the threepoints is prevented from being unconditionally determined by the outsidediameter of each detecting means. That is, any desired three points ofthe part can be detected for accurate detection without regard to thesize of the part.

[0120] (4) Before the assembling position of the part is adjusted,intermediate members applied with adhesive are brought to a portionwhere they are capable of contacting the part and part support. Itfollows that the adhesive is spread by the relative movement of the partand intermediate members occurring during adjustment. Consequently, theadhesive is provided with uniform thickness.

[0121] (5) The adhesive is implemented by photocuring adhesive curablewhen illuminated by light. After the adjustment of the position of thepart, the adhesive is cured by light. This prevents the adhesive fromcuring during adjustment and thereby prevents the part from being fixedin a defective position.

[0122] (6) The intermediate members are formed of a material transparentfor light, so that the adhesive is cured via the intermediate members.The light can therefore be radiated over a broad range in order toreduce the curing time of the adhesive.

[0123] (7) Part holding means varies the position of the part such thatthe preselected three points of the part are detected by positiondetecting means. The part can therefore be extremely accurately fixed tothe part support.

[0124] (8) Nozzle holes customarily formed in the surface of an ink jethead are used as a reference for adjusting the position of the head.This makes it needless to provide, e.g., special parts to be detected bythe position detecting means on the head.

[0125] (9) The position detecting means again detects the position ofthe part fixed to the part support, so that the quality of the part canbe easily and accurately determined during assembly. This eliminates theneed for an exclusive checking step independent of the assemblingprocedure.

[0126] (10) After a jig loaded with the part and part support has beenconveyed to a preselected assembling position, the part is adjusted inposition and then mounted to the part support. The part supporttherefore does not have to be directly retained by a chuck. In addition,while the part support is held in a position ready to be assembled, itsportions for accommodating the part and intermediate members are open orfreely accessible. This allows the part and intermediate members to beeasily held by chucks.

[0127] (11) The jig is moved back and forth by jig conveying meansbetween a setting position where it is loaded with the part support,part and intermediate members and the above assembling position. Theoperator can therefore load the jig with the above parts and take outthe jig at carrying the assembled parts a single position. Thisfacilitates the loading and removal of parts from the jig and reducesthe operation time to thereby promote the efficient assembly of parts.

[0128] (12) When the operator sets the parts on the jig or removes theproduct from the jig, the operator is prevented from touching assemblingmeans accurately positioned and arranged at the assembling position orcausing the parts to contact the assembling means by accident. Theassembling means is therefore protected from dislocation, and theoperator is free from damage.

[0129] (13) Paths between two or more setting positions and theassembling position along which the jig conveying means conveys jigs canbe switched by path switching means. Therefore, it is possible to conveyone jig conveyed from one setting position to the assembling positionand completed assembly there to the other setting position. It is alsopossible to feed one jig from one setting position to the assemblingposition and set, while the parts set on the jig are assembled, parts onthe other jig located at the other setting position. This reduces theoperator's waiting time at the time of setting of the structural partson the jig and thereby further enhances efficient assembly.

[0130] (14) When the parts are set on the part supporting portion of thejig, flat cables extending out from parts can be received in a pockedformed in the part supporting portion. The flat cables are thereforeprotected from damage when the parts are conveyed or retained by chucks.

[0131] (15) While a head support is located at a predetermined positionon the jig by a head support holding portion, stubs included in the headsupport holding portion are received in slide bearings included in thehead support and used to move the head back and forth in a preselectedprinting direction. The stubs therefore define a reference shaft whenthe head is fixed to the head support and al low the head to beextremely accurately positioned relative to the head support.

[0132] (16) The head is positioned on the part supporting portion withits ink feed portion mating with a hole formed in the part supportingportion. The ink feed portion conventional with the head obviated theneed for special positioning means.

[0133] (17) Air chucks move the intermediate members to a preselectedmounting position between the part and part support while retaining themby suction. The suction is adjustable to vary the retaining forces ofthe air chucks. Therefore, sophisticated adjustment and controlparticular to mechanical means for clamping the intermediate members isnot necessary.

[0134] (18) The suction required of the air chucks decreases with adecrease in the size of the intermediate members, so that the chucks canbe provided with a miniature and simple configuration. Even when thenumber of intermediate members is increased, the air chucks should onlyhave the number of their suction surface increased accordingly.

[0135] (19) The intermediate members are retained on the suctionsurfaces of the air chucks in substantially the same position as whenthey are located at the mounting position between the part and the partsupport. Therefore, during the conveyance of the intermediate members tothe assembly position, it is not necessary to adjust their positions onthe air chucks. This successfully simplifies control over the airchucks.

[0136] (20) A plurality of intermediate members arranged at preselectedpositions can be retained by each air chuck at the same time. The airchuck can therefore bring the intermediate members to the mountingposition between the part and the part support at the same time.

[0137] (21) Air is blown out via the passageway of each air chuck inorder to press the intermediate members retained on the chuck againstthe mounting position. Therefore, when the intermediate members are tobe set at the mounting position, it is not necessary to delicatelycontrol the position of the air chuck, i.e., the positions of theintermediate members retained by the air chuck. This further simplifiescontrol over the air chucks.

[0138] (22) The suction or vacuum for retaining the intermediate membersand the jets of air for releasing them share the same holes formed ineach air chuck. The air chuck is therefore simple in configuration.

[0139] (23) Each air chuck retains the intermediate members by suctionand then releases them by air in the same position. This allows theintermediate members to behave in substantially the same manner whensucked by the air chuck and when released at the assembling position.Therefore, even when the intermediate members are slightly dislocatedwhen sucked by the air chuck, the dislocation can be canceled at thetime of positioning.

[0140] (24) While the air chuck retaining the intermediate membersconveys them to the mounting position, adhesive applying means appliesadhesive to the preselected surfaces of the intermediate members. It istherefore possible to locate the adhesive applying means at a positionremote from the mounting position. It follows that other units arrangedat the mounting position can be laid out with greater freedom.

[0141] (25) Because the adhesive applying means applies the adhesive tothe intermediate members before the intermediate members arrive at themounting position, the intermediate members are surely located at themounting position due to the viscosity of the adhesive. This preventsthe intermediate members from being displaced after being laid at themounting position.

[0142] Various modifications will become possible for those skilled inthe art after receiving the teachings of the present disclosure withoutdeparting from the scope thereof.

What is claimed is:
 1. A method of assembling a part and a part supportby use of adhesive via an intermediate member provided between said partand said part support, said method comprising the steps of: positioningand holding the part support at a preselected assembling position; andvarying, while holding the part in a position adjustable relative to thepart support, said position of said part and detecting three preselectedpoints of said part to thereby adjust a position in which said part isto be mounted to said part support.
 2. A method as claimed in claim 1 ,wherein when a plurality of identical parts are to be sequentiallymounted to the part support in an identical condition, positionadjustment data derived from a position adjustment of a preceding partrelative to said part support are referenced as position adjustment datafor a following part.
 3. A method as claimed in claim 1 , wherein thethree preselected points of the part are present on a single surface ofsaid part, at least three optical detecting means respectively detectingsaid three preselected points with optical axes thereof inclinedrelative to said single surface.
 4. A method as claimed in claim 1 ,further comprising the step of causing the intermediate member appliedwith the adhesive to contact the part and the part support before saidpart is adjusted in position.
 5. A method as claimed in claim 1 ,wherein the adhesive comprises photocuring adhesive curable whenilluminated by light, said method further comprising the step of curingsaid adhesive by radiating light toward said adhesive.
 6. A method asclaimed in claim 5 , wherein the intermediate member is formed of amaterial transparent for the light, the adhesive being cured by thelight via said intermediate member.
 7. An apparatus for assembling apart and a part support by use of adhesive via an intermediate memberprovided between said part and said part support, said apparatuscomprising: part support holding means for positioning and holding thepart support at a preselected assembling position; part supporting meansfor supporting the part in a position variable relative to the partsupport held by said part support holding means; part position detectingmeans for detecting preselected three points of the part supported bysaid part supporting means; and part position adjusting means foradjusting, based on positions of said three preselected points detectedby said part position detecting means, a position of the part relativeto the part support.
 8. An apparatus as claimed in claim 7 , wherein thepart comprises an ink jet head, said part position detecting meanscomprising at least three solid imaging devices for respectivelydetecting, in directions inclined relative to a head surface of said inkjet head, preselected three of nozzle holes formed in said head surfacefor ejecting ink.
 9. An apparatus as claimed in claim 7 , furthercomprising decision means for again detecting said three preselectedpoints of the part adhered to the part support by the adhesive tothereby determine whether or not said part is acceptable.
 10. A methodof assembling a part and a part support by use of adhesive via anintermediate member provided between said part and said part support,said method comprising the steps of: preparing a jig including a partsupport holding portion for positioning and holding the part supportsuch that said part support remains in an assembly position andmaintains portions thereof for mounting the part and the intermediatemember open, a part supporting portion for supporting said part in sucha manner as to secure a region for adjusting a position of said partrelative to said part support positioned on said part support holdingportion, and an intermediate member supporting portion for supportingthe intermediate member in a position ready to be mounted to said partsupport positioned on said part supporting holding portion; mounting thepart, the part support member and the intermediate member to said jig;and adjusting a position of the part relative to the part support andmounting the intermediate member after positioning said jig at apreselected assembling position.
 11. An apparatus for assembling a partand a part support by use of adhesive via an intermediate memberprovided between said part and said part support, said apparatuscomprising: a jig including a part support holding portion forpositioning and holding the part support such that said part supportremains in an assembly position and maintains portions thereof formounting the part and the intermediate member open, a part supportingportion for supporting said part in such a manner as to secure a regionfor adjusting a position of said part relative to said part supportpositioned on said part support holding portion, and an intermediatemember supporting portion for supporting said intermediate member in aposition ready to be mounted to said part support positioned on saidpart supporting holding portion; and jig positioning means forpositioning at a preselected assembly position said jig loaded with thepart, the part support member and the intermediate member in said partsupporting portion, said part support holding portion and saidintermediate member supporting portion, respectively.
 12. An apparatusas claimed in claim 11 , further comprising jig conveying means forconveying said jig back and forth between a setting position where thepart support, the part and the intermediate member are set on said jigand said preselected assembly position.
 13. An apparatus as claimed inclaim 12 , wherein at least two setting positions are provided, saidapparatus further comprising path switching means for selecting one oftwo paths along which said jig conveying means conveys said jig betweensaid two setting positions and said preselected assembly position. 14.An apparatus as claimed in claim 11 , wherein the part includes a flatcable, said part supporting portion of said jig including a pocket forreceiving said flat cable.
 15. An apparatus as claimed in claim 11 ,wherein the part and the part support comprise an ink jet head and ahead support, respectively, said part support holding portion of saidjig including stubs capable of mating with slide bearings included insaid head support.
 16. An apparatus as claimed in claim 11 , wherein thepart comprises an ink jet head including an ink feed portion protrudingfrom said ink jet head, said part supporting portion of said jigincluding a hole capable of mating with said ink feed portion.
 17. In apart assembling apparatus including holding and conveying means forholding an intermediate member expected to fix a part and a part supportvia adhesive and conveying said intermediate member to a preselectedmounting position between said part and said part support, said holdingand conveying means comprises an air chuck for retaining saidintermediate member thereon by vacuum.
 18. An apparatus as claimed inclaim 17 , wherein said air chuck includes a surface for sucking andretaining the intermediate member such that said intermediate member isretained on said air chuck in a substantially same position as when saidintermediate member will be located at a preselected mounting positionbetween the part and the part support.
 19. An apparatus as claimed inclaim 17 , wherein said air chuck includes a plurality of holdingportions capable of simultaneously sucking a plurality of intermediatemembers located at said preselected mounting position.
 20. An apparatusas claimed in claim 17 , wherein said air chuck includes a passagewayfor jetting air for pressing the intermediate member conveyed by saidair chuck against the preselected mounting position between the part andthe part support.
 21. An apparatus as claimed in claim 20 , wherein saidpassageway sucks air for generating vacuum for retaining theintermediate member.
 22. An apparatus as claimed in claim 17 , furthercomprising adhesive applying means located on a path along which saidair chuck conveys the intermediate member toward said preselectedmounting position, said adhesive applying means including an adhesivefeed portion facing adhering surfaces of said intermediate member forapplying adhesive to said adhering surfaces.